Sensor materials that modify both an optical and electrical material parameter on the basis of a modification of a relevant environmental parameter may be required in at least some applications. For example, in CO2 sensors made of soft polymers having a colorant and an auxiliary base, both the color and the conductivity of the pH indicator may be modified.
In combinatorial chemistry, in which, for example, a large number of varying samples, possibly having slightly varying compositions, are to be examined, corresponding materials may be examined electrically or optically independently of one another. For example, corresponding material samples may be charged with carbon dioxide (CO2), while an electrical or optical parameter of the sample is measured.
Through the effect of the relevant environmental parameter, the material to be tested changes due to chemical conversions during the first measurement, for example, of the electrical parameter. This chemical conversion may falsify a subsequent second measurement, or prevent the subsequent measurement, for example, the optical measurement of an optical parameter of the material to be tested, from being performed using the same sample.
Thus, it is believed to be disadvantageous in that the measurement of the relevant parameters of the same sample may not be performed under identical measurement conditions.